From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9417211C8D for ; Wed, 4 Oct 2023 11:07:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D39D9C433C7; Wed, 4 Oct 2023 11:07:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1696417639; bh=1JJrIUPl6pbHzZ7I1g6oBNmULdlUHsuIiITpgEf24Mw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hhs3iQMnZx4oR08DZ/GXEIWmgD/VHwaRYw1qbKslBmAbCUM9ZyX25b0+KROSz41FY rRv07clWP2HIEdfy10yH9XaQbE5BMbVlNn5roem8f5jXtDmbH2ebesao2KAylq12Dw TDt/dD698mjX0ymhnx9LD23Of1aDtzEtL7yBKjxkhGH1AyBct8Co5+hDF9Ocq30QlH q7P2GQnEwSzRpli39K+TnLPNfZLwamYKoC2c7ptjaS+Cm7fodSp1GFRLU7pYkzyAL2 048rvKKMkUXmnz55TIYo4hVordZq6g4y/in9hXRRrzn7EmWqgD0gdotKUswvHkwtsl DvM7n2d8mwSpg== Date: Wed, 4 Oct 2023 13:07:14 +0200 From: Simon Horman To: =?utf-8?B?S8O2cnk=?= Maincent Cc: Michal Kubecek , "David S. Miller" , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Maxime Chevallier , stable@vger.kernel.org, thomas.petazzoni@bootlin.com, Eric Dumazet , Jakub Kicinski , Paolo Abeni Subject: Re: [PATCH net 1/1] ethtool: Fix mod state of verbose no_mask bitset Message-ID: References: <20231003085653.3104411-1-kory.maincent@bootlin.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20231003085653.3104411-1-kory.maincent@bootlin.com> On Tue, Oct 03, 2023 at 10:56:52AM +0200, Köry Maincent wrote: > From: Kory Maincent > > A bitset without mask in a _SET request means we want exactly the bits in > the bitset to be set. This works correctly for compact format but when > verbose format is parsed, ethnl_update_bitset32_verbose() only sets the > bits present in the request bitset but does not clear the rest. The commit > 6699170376ab fixes this issue by clearing the whole target bitmap before we > start iterating. The solution proposed brought an issue with the behavior > of the mod variable. As the bitset is always cleared the old val will > always differ to the new val. > > Fix it by adding a new temporary variable which save the state of the old > bitmap. > > Fixes: 6699170376ab ("ethtool: fix application of verbose no_mask bitset") > Signed-off-by: Kory Maincent > Cc: stable@vger.kernel.org > --- > net/ethtool/bitset.c | 25 +++++++++++++++++++------ > 1 file changed, 19 insertions(+), 6 deletions(-) > > diff --git a/net/ethtool/bitset.c b/net/ethtool/bitset.c > index 0515d6604b3b..95f11b0a38b4 100644 > --- a/net/ethtool/bitset.c > +++ b/net/ethtool/bitset.c > @@ -432,7 +432,9 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits, > struct netlink_ext_ack *extack, bool *mod) > { > struct nlattr *bit_attr; > + u32 *tmp = NULL; > bool no_mask; > + bool dummy; > int rem; > int ret; > > @@ -448,8 +450,11 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits, > } > > no_mask = tb[ETHTOOL_A_BITSET_NOMASK]; > - if (no_mask) > - ethnl_bitmap32_clear(bitmap, 0, nbits, mod); > + if (no_mask) { > + tmp = kcalloc(nbits, sizeof(u32), GFP_KERNEL); > + memcpy(tmp, bitmap, nbits); Hi Köry, I'm no expert on etnhl bitmaps. But the above doesn't seem correct to me. Given that sizeof(u32) == 4: * The allocation is for nbits * 4 bytes * The copy is for its for nbits bytes * I believe that bitmap contains space for the value followed by a mask. So it seems to me the size of bitmap, in words, is DIV_ROUND_UP(nbits, 32) * 2 And in bytes: DIV_ROUND_UP(nbits, 32) * 16 But perhaps only half is needed if only the value part of tmp is used. If I'm on the right track here I'd suggest helpers might be in order. > + ethnl_bitmap32_clear(bitmap, 0, nbits, &dummy); > + } > > nla_for_each_nested(bit_attr, tb[ETHTOOL_A_BITSET_BITS], rem) { > bool old_val, new_val; > @@ -458,13 +463,18 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits, > if (nla_type(bit_attr) != ETHTOOL_A_BITSET_BITS_BIT) { > NL_SET_ERR_MSG_ATTR(extack, bit_attr, > "only ETHTOOL_A_BITSET_BITS_BIT allowed in ETHTOOL_A_BITSET_BITS"); > - return -EINVAL; > + ret = -EINVAL; > + goto out; > } > ret = ethnl_parse_bit(&idx, &new_val, nbits, bit_attr, no_mask, > names, extack); > if (ret < 0) > - return ret; > - old_val = bitmap[idx / 32] & ((u32)1 << (idx % 32)); > + goto out; > + if (no_mask) > + old_val = tmp[idx / 32] & ((u32)1 << (idx % 32)); > + else > + old_val = bitmap[idx / 32] & ((u32)1 << (idx % 32)); > + > if (new_val != old_val) { > if (new_val) > bitmap[idx / 32] |= ((u32)1 << (idx % 32)); > @@ -474,7 +484,10 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits, > } > } > > - return 0; > + ret = 0; > +out: > + kfree(tmp); > + return ret; > } > > static int ethnl_compact_sanity_checks(unsigned int nbits, > -- > 2.25.1 > >